The original Church organ was built by the Positive Organ Company of London which produced a considerable number of small one manual instruments. The firm was founded by Thomas Casson (1842-1910) of Denbigh, a banker turned organ builder whose ideas of organ specifications were advanced for the time.
The organ had five stops of eight foot (unison) pitch, plus an octave coupler to produce a brighter sound. Initially pumped by hand, it is about 100 years old.
The rebuilt organ has 10 stops, half of which are above unison pitch, so producing a much brighter, fuller tone. The melodic diapason and melodic bass stops give the effect of a two manual organ with pedals and four new thumb pistons allow the player to make instant stop changes.
Further details on Thomas Casson can be found here